I'm trying to create a loop to go over the last bars and figure out what the average gain is when the hma is sloping up. But I'm getting an error I don't understand. Is it not possible to have a loop inside a function?
My code:
// Get Average Gains on long streaks
getAverageGain(hmaValue) =>
gainStart = 0.00
gainAmount = 0.00
gainCount = 0
gaining = hmaValue[1] < hmaValue
for i=0 to 2000
if gaining[i] and not gaining[i+1]
gainStart := hmaValue[i]
if gaining[i+1] and not gaining[i] and gainStart != 0.00
gainAmount += ((hmaValue[i+1] - gainStart) / gainStart) * 100
gainCount ++
gainAmount/gainCount
There is no ++ operator in pinescript. Change it to gainCount := gainCount + 1.
You can see the list of operators in pinescript from here.
Problem was with the double + sign....not the for loop
gainCount ++
Unfortunately Pine-script's error messages aren't always clear enough
Related
Can anyone please direct me to an example of where one can send a user input variable to a checking function or module & return the validated input assigning / updating the initialised variable?. I am trying to re-create something I did in C++ many years ago where I am trying to validate an integer! In this particular case that the number of bolts input in a building frame connection is such. Any direction would be greatly appreciated as my internet searches and trawls through my copy of Python A Crash Course have yet to shed any light! Many thanks in anticipation that someone will feel benevolent towards a Python newbie!
Regards Steve
Below is one on my numerous attempts at this, really I would just like to abandon and use While and a function call. In this one apparently I am not allowed to put > (line 4) between str and int, this desite my attempt to force N to be int - penultimate line!
def int_val(N):
#checks
# check 1. n > 0 for real entries
N > 0
isinstance(N, int)
N=N
return N
print("N not ok enter again")
#N = input("Input N the Number of bolts ")
# Initialiase N=0
#N = 0
# Enter the number of bolts
N = input("Input N the Number of bolts ")
int_val(N)
print("no of bolts is", N)
Is something like this what you have in mind? It takes advantage of the fact that using the built-in int function will convert a string to an integer if possible, but otherwise throw a ValueError.
def str_to_posint(s):
"""Return value if converted and greater than zero else None."""
try:
num = int(s)
return num if num > 0 else None
except ValueError:
return None
while True:
s = input("Enter number of bolts: ")
if num_bolts := str_to_posint(s):
break
print(f"Sorry, \"{s}\" is not a valid number of bolts.")
print(f"{num_bolts = }")
Output:
Enter number of bolts: twenty
Sorry, "twenty" is not a valid number of bolts.
Enter number of bolts: 20
num_bolts = 20
def str_to_posint(s):
"""Return value if converted and greater than zero else None."""
try:
num = int(s)
return num if num > 0 else None
except ValueError:
return None
while True:
s = input("Enter number of bolts: ")
if num_bolts := str_to_posint(s):
break
print(f"Sorry, "{s}" is not a valid number of bolts.")
print(f"{num_bolts = }")
I've got a little MatLab script, which I try to understand. It doesn't do very much. It only reads a text from a file and encode and decode it with the Huffman-functions.
But it throws an error while decoding:
"error: out of memory or dimension too large for Octave's index type
error: called from huffmandeco>dict2tree at line 95 column 19"
I don't know why, because I debugged it and don't see a large index type.
I added the part which calculates p from the input text.
%text is a random input text file in ASCII
%calculate the relative frequency of every Symbol
for i=0:127
nlet=length(find(text==i));
p(i+1)=nlet/length(text);
end
symb = 0:127;
dict = huffmandict(symb,p); % Create dictionary
compdata = huffmanenco(fdata,dict); % Encode the data
dsig = huffmandeco(compdata,dict); % Decode the Huffman code
I can oly use octave instead of MatLab. I don't know, if there is an unexpected error. I use the Octave Version 6.2.0 on Win10. I tried the version for large data, it didn't change anything.
Maybe anyone knows the error in this context?
EDIT:
I debugged the code again. In the function huffmandeco I found the following function:
function tree = dict2tree (dict)
L = length (dict);
lengths = zeros (1, L);
## the depth of the tree is limited by the maximum word length.
for i = 1:L
lengths(i) = length (dict{i});
endfor
m = max (lengths);
tree = zeros (1, 2^(m+1)-1)-1;
for i = 1:L
pointer = 1;
word = dict{i};
for bit = word
pointer = 2 * pointer + bit;
endfor
tree(pointer) = i;
endfor
endfunction
The maximum length m in this case is 82. So the function calculates:
tree = zeros (1, 2^(82+1)-1)-1.
So it's obvious why the error called a too large index type.
But there must be a solution or another error, because the code is tested before.
I haven't weeded through the code enough to know why yet, but huffmandict is not ignoring zero-probability symbols the way it claims to. Nor have I been able to find a bug report on Savannah, but again I haven't searched thoroughly.
A workaround is to limit the symbol list and their probabilities to only the symbols that actually occur. Using containers.Map would be ideal, but in Octave you can do that with a couple of the outputs from unique:
% Create a symbol table of the unique characters in the input string
% and the indices into the table for each character in the string.
[symbols, ~, inds] = unique(textstr);
inds = inds.'; % just make it easier to read
For the string
textstr = 'Random String Input.';
the result is:
>> symbols
symbols = .IRSadgimnoprtu
>> inds
inds =
Columns 1 through 19:
4 6 11 7 12 10 1 5 15 14 9 11 8 1 3 11 13 16 15
Column 20:
2
So the first symbol in the input string is symbols(4), the second is symbols(6), and so on.
From there, you just use symbols and inds to create the dictionary and encode/decode the signal. Here's a quick demo script:
textstr = 'Random String Input.';
fprintf("Starting string: %s\n", textstr);
% Create a symbol table of the unique characters in the input string
% and the indices into the table for each character in the string.
[symbols, ~, inds] = unique(textstr);
inds = inds.'; % just make it easier to read
% Calculate the frequency of each symbol in table
% max(inds) == numel(symbols)
p = histc(inds, 1:max(inds))/numel(inds);
dict = huffmandict(symbols, p);
compdata = huffmanenco(inds, dict);
dsig = huffmandeco(compdata, dict);
fprintf("Decoded string: %s\n", symbols(dsig));
And the output:
Starting string: Random String Input.
Decoded string: Random String Input.
To encode strings other than the original input string, you would have to map the characters to symbol indices (ensuring that all symbols in the string are actually present in the symbol table, obviously):
>> [~, s_idx] = ismember('trogdor', symbols)
s_idx =
15 14 12 8 7 12 14
>> compdata = huffmanenco(s_idx, dict);
>> dsig = huffmandeco(compdata, dict);
>> fprintf("Decoded string: %s\n", symbols(dsig));
Decoded string: trogdor
I want to run a MATLAB script M-file to reconstruct a point cloud in Octave. Therefore I had to rewrite some parts of the code to make it compatible with Octave. Actually the M-file works fine in Octave (I don't get any errors) and also the plotted point cloud looks good at first glance, but it seems that the variables are only half the size of the original MATLAB variables. In the attached screenshots you can see what I mean.
Octave:
MATLAB:
You can see that the dimension of e.g. M in Octave is 1311114x3 but in MATLAB it is 2622227x3. The actual number of rows in my raw file is 2622227 as well.
Here you can see an extract of the raw file (original data) that I use.
Rotation angle Measured distance
-0,090 26,295
-0,342 26,294
-0,594 26,294
-0,846 26,295
-1,098 26,294
-1,368 26,296
-1,620 26,296
-1,872 26,296
In MATLAB I created my output variable as follows.
data = table;
data.Rotationangle = cell2mat(raw(:, 1));
data.Measureddistance = cell2mat(raw(:, 2));
As there is no table function in Octave I wrote
data = cellfun(#(x)str2num(x), strrep(raw, ',', '.'))
instead.
Octave also has no struct2array function, so I had to replace it as well.
In MATLAB I wrote.
data = table2array(data);
In Octave this was a bit more difficult to do. I had to create a struct2array function, which I did by means of this bug report.
%% Create a struct2array function
function retval = struct2array (input_struct)
%input check
if (~isstruct (input_struct) || (nargin ~= 1))
print_usage;
endif
%convert to cell array and flatten/concatenate output.
retval = [ (struct2cell (input_struct)){:}];
endfunction
clear b;
b.a = data;
data = struct2array(b);
Did I make a mistake somewhere and could someone help me to solve this problem?
edit:
Here's the part of my script where I'm using raw.
delimiter = '\t';
startRow = 5;
formatSpec = '%s%s%[^\n\r]';
fileID = fopen(filename,'r');
dataArray = textscan(fileID, formatSpec, 'Delimiter', delimiter, 'HeaderLines' ,startRow-1, 'ReturnOnError', false, 'EndOfLine', '\r\n');
fclose(fileID);
%% Convert the contents of columns containing numeric text to numbers.
% Replace non-numeric text with NaN.
raw = repmat({''},length(dataArray{1}),length(dataArray)-1);
for col=1:length(dataArray)-1
raw(1:length(dataArray{col}),col) = mat2cell(dataArray{col}, ones(length(dataArray{col}), 1));
end
numericData = NaN(size(dataArray{1},1),size(dataArray,2));
for col=[1,2]
% Converts text in the input cell array to numbers. Replaced non-numeric
% text with NaN.
rawData = dataArray{col};
for row=1:size(rawData, 1)
% Create a regular expression to detect and remove non-numeric prefixes and
% suffixes.
regexstr = '(?<prefix>.*?)(?<numbers>([-]*(\d+[\.]*)+[\,]{0,1}\d*[eEdD]{0,1}[-+]*\d*[i]{0,1})|([-]*(\d+[\.]*)*[\,]{1,1}\d+[eEdD]{0,1}[-+]*\d*[i]{0,1}))(?<suffix>.*)';
try
result = regexp(rawData(row), regexstr, 'names');
numbers = result.numbers;
% Detected commas in non-thousand locations.
invalidThousandsSeparator = false;
if numbers.contains('.')
thousandsRegExp = '^\d+?(\.\d{3})*\,{0,1}\d*$';
if isempty(regexp(numbers, thousandsRegExp, 'once'))
numbers = NaN;
invalidThousandsSeparator = true;
end
end
% Convert numeric text to numbers.
if ~invalidThousandsSeparator
numbers = strrep(numbers, '.', '');
numbers = strrep(numbers, ',', '.');
numbers = textscan(char(numbers), '%f');
numericData(row, col) = numbers{1};
raw{row, col} = numbers{1};
end
catch
raw{row, col} = rawData{row};
end
end
end
You don't see any raw in my workspaces because I clear all temporary variables before I reconstruct my point cloud.
Also my original data in row 1311114 and 1311115 look normal.
edit 2:
As suggested here is a small example table to clarify what I want and what MATLAB does with the table2array function in my case.
data =
-0.0900 26.2950
-0.3420 26.2940
-0.5940 26.2940
-0.8460 26.2950
-1.0980 26.2940
-1.3680 26.2960
-1.6200 26.2960
-1.8720 26.2960
With the struct2array function I used in Octave I get the following array.
data =
-0.090000 26.295000
-0.594000 26.294000
-1.098000 26.294000
-1.620000 26.296000
-2.124000 26.295000
-2.646000 26.293000
-3.150000 26.294000
-3.654000 26.294000
If you compare the Octave array with my original data, you can see that every second row is skipped. This seems to be the reason for 1311114 instead of 2622227 rows.
edit 3:
I tried to solve my problem with the suggestions of #Tasos Papastylianou, which unfortunately was not successful.
First I did the variant with a struct.
data = struct();
data.Rotationangle = [raw(:,1)];
data.Measureddistance = [raw(:,2)];
data = cell2mat( struct2cell (data ).' )
But this leads to the following structure in my script. (Unfortunately the result is not what I would like to have as shown in edit 2. Don't be surprised, I only used a small part of my raw file to accelerate the run of my script, so here are only 769 lines.)
[766,1] = -357,966
[767,1] = -358,506
[768,1] = -359,010
[769,1] = -359,514
[1,2] = 26,295
[2,2] = 26,294
[3,2] = 26,294
[4,2] = 26,296
Furthermore I get the following error.
error: unary operator '-' not implemented for 'cell' operands
error: called from
Cloud_reconstruction at line 137 column 11
Also the approach with the dataframe octave package didn't work. When I run the following code it leads to the error you can see below.
dataframe2array = #(df) cell2mat( struct(df).x_data );
pkg load dataframe;
data = dataframe();
data.Rotationangle = [raw(:, 1)];
data.Measureddistance = [raw(:, 2)];
dataframe2array(data)
error:
warning: Trying to overwrite colum names
warning: called from
df_matassign at line 147 column 13
subsasgn at line 172 column 14
Cloud_reconstruction at line 106 column 20
warning: Trying to overwrite colum names
warning: called from
df_matassign at line 176 column 13
subsasgn at line 172 column 14
Cloud_reconstruction at line 106 column 20
warning: Trying to overwrite colum names
warning: called from
df_matassign at line 147 column 13
subsasgn at line 172 column 14
Cloud_reconstruction at line 107 column 23
warning: Trying to overwrite colum names
warning: called from
df_matassign at line 176 column 13
subsasgn at line 172 column 14
Cloud_reconstruction at line 107 column 23
error: RHS(_,2): but RHS has size 768x1
error: called from
df_matassign at line 179 column 11
subsasgn at line 172 column 14
Cloud_reconstruction at line 107 column 23
Both error messages refer to the following part of my script where I'm doing the reconstruction of the point cloud in cylindrical coordinates.
distLaserCenter = 47; % Distance between the pipe centerline and the blind zone in mm
m = size(data,1); % Find the length of the first dimension of data
zincr = 0.4/360; % z increment in mm per deg
data(:,1) = -data(:,1);
for i = 1:m
data(i,2) = data(i,2) + distLaserCenter;
if i == 1
data(i,3) = 0;
elseif abs(data(i,1)-data(i-1)) < 100
data(i,3) = data(i-1,3) + zincr*(data(i,1)-data(i-1));
else abs(data(i,1)-data(i-1)) > 100;
data(i,3) = data(i-1,3) + zincr*(data(i,1)-(data(i-1)-360));
end
end
To give some background information for a better understanding. The script is used to reconstruct a pipe as a point cloud. The surface of the pipe was scanned from inside with a laser and the laser measured several points (distance from laser to the inner wall of the pipe) at each deg of rotation. I hope this helps to understand what I want to do with my script.
Not sure exactly what you're trying to do, but here's a toy example of how a struct could be used in an equivalent manner to a table:
matlab:
data = table;
data.A = [1;2;3;4;5];
data.B = [10;20;30;40;50];
table2array(data)
octave:
data = struct();
data.A = [1;2;3;4;5];
data.B = [10;20;30;40;50];
cell2mat( struct2cell (data ).' )
Note the transposition operation (.') before passing the result to cell2mat, since in a table, the 'fieldnames' are arranged horizontally in columns, whereas the struct2cell ends up arranging what used to be the 'fieldnames' as rows.
You might also be interested in the dataframe octave package, which performs similar functions to matlab's table (or in fact, R's dataframe object): https://octave.sourceforge.io/dataframe/ (you can install this by typing pkg install -forge dataframe in your console)
Unfortunately, the way to display the data as an array is still not ideal (see: https://stackoverflow.com/a/55417141/4183191), but you can easily convert that into a tiny function, e.g.
dataframe2array = #(df) cell2mat( struct(df).x_data );
Your code can then become:
pkg load dataframe;
data = dataframe();
data.A = [1;2;3;4;5];
data.B = [10;20;30;40;50];
dataframe2array(data)
I am facing a issue, here is my script. some end or bracket issue but I have checked noting is missing.
function [h, display_array] = displayData(X, example_width)
%DISPLAYDATA Display 2D data in a nice grid
% [h, display_array] = DISPLAYDATA(X, example_width) displays 2D data
% stored in X in a nice grid. It returns the figure handle h and the
% displayed array if requested.
% Set example_width automatically if not passed in
if ~exist('example_width', 'var') || isempty(example_width)
example_width = round(sqrt(size(X, 2)));
end
% Gray Image
colormap(gray);
% Compute rows, cols
[m n] = size(X);
example_height = (n / example_width);
% Compute number of items to display
display_rows = floor(sqrt(m));
display_cols = ceil(m / display_rows);
% Between images padding
pad = 1;
% Setup blank display
display_array = - ones(pad + display_rows * (example_height + pad), ...
pad + display_cols * (example_width + pad));
% Copy each example into a patch on the display array
curr_ex = 1;
for j = 1:display_rows
for i = 1:display_cols
if curr_ex > m,
break;
end
% Copy the patch
% Get the max value of the patch
max_val = max(abs(X(curr_ex, :)));
display_array(pad + (j - 1) * (example_height + pad) +
(1:example_height), ...
pad + (i - 1) * (example_width + pad) +
(1:example_width)) = ...
reshape(X(curr_ex, :),
example_height, example_width) / max_val;
curr_ex = curr_ex + 1;
end
if curr_ex > m,
break;
end
end
% Display Image
h = imagesc(display_array, [-1 1]);
% Do not show axis
axis image off
drawnow;
end
ERROR:
displayData
parse error near line 86 of file C:\Users\ALI\displayData.m
syntax error
Pls guide which is the error in the script, this script is already written in
the coursera so its must be error free.
You seem to have modified the code, and moved the "ellipsis" operator (i.e. ...) or the line that is supposed to follow it, in several places compared to the original code in coursera.
Since the point of the ellipsis operator is to appear at the end of a line, denoting that the line that follows is meant to be a continuation of the line before, then moving either the ellipsis or the line below it will break the code.
E.g.
a = 1 + ... % correct use of ellipsis, code continues below
2 % treated as one line, i.e. a = 1 + 2
vs
a = 1 + % without ellipsis, the line is complete, and has an error
... 2 % bad use of ellipsis; also anything to the right of '...' is ignored
vs
a = 1 + ... % ellipsis used properly so far
% but the empty line here makes the whole 'line' `a = 1 +` which is wrong
2 % This is a new instruction
Many random-number generators return floating numbers between 0 and 1.
What's the best and correct way to get integers between a and b?
Divide the interval [0,1] in B-A+1 bins
Example A=2, B=5
[----+----+----+----]
0 1/4 1/2 3/4 1
Maps to 2 3 4 5
The problem with the formula
Int (Rnd() * (B-A+1)) + A
is that your Rnd() generation interval is closed on both sides, thus the 0 and the 1 are both possible outputs and the formula gives 6 when the Rnd() is exactly 1.
In a real random distribution (not pseudo), the 1 has probability zero. I think it is safe enough to program something like:
r=Rnd()
if r equal 1
MyInt = B
else
MyInt = Int(r * (B-A+1)) + A
endif
Edit
Just a quick test in Mathematica:
Define our function:
f[a_, b_] := If[(r = RandomReal[]) == 1, b, IntegerPart[r (b - a + 1)] + a]
Build a table with 3 10^5 numbers in [1,100]:
table = SortBy[Tally[Table[f[1, 100], {300000}]], First]
Check minimum and maximum:
In[137]:= {Max[First /# table], Min[First /# table]}
Out[137]= {100, 1}
Lets see the distribution:
BarChart[Last /# SortBy[Tally[Table[f[1, 100], {300000}]], First],
ChartStyle -> "DarkRainbow"]
X = (Rand() * (B - A)) + A
Another way to look at it, where r is your random number in the range 0 to 1:
(1-r)a + rb
As for your additional requirement of the result being an integer, maybe (apart from using built in casting) the modulus operator can help you out. Check out this question and the answer:
Expand a random range from 1–5 to 1–7
Well, why not just look at how Python does it itself? Read random.py in your installation's lib directory.
After gutting it to only support the behavior of random.randint() (which is what you want) and removing all error checks for non-integer or out-of-bounds arguments, you get:
import random
def randint(start, stop):
width = stop+1 - start
return start + int(random.random()*width)
Testing:
>>> l = []
>>> for i in range(2000000):
... l.append(randint(3,6))
...
>>> l.count(3)
499593
>>> l.count(4)
499359
>>> l.count(5)
501432
>>> l.count(6)
499616
>>>
Assuming r_a_b is the desired random number between a and b and r_0_1 is a random number between 0 and 1 the following should work just fine:
r_a_b = (r_0_1 * (b-a)) + a