I have a self-defined function in Mathematica, which has the following syntax:
outputval = myfunc[r, sigma, S, K, T, lambda, eta1, eta2, p]
When the function is called as above with numeric input values, it outputs a single output value.
For each input variable I have 5 different values. I want to input all combinations of all 5 values of the 9 input variables in my function and export a CSV file containing the 9 input values and their respective output value in the 10th column.
I am very new to Mathematica and I have no clue how to do so. Any help is appreciated:)
A small example will illustrate how to get what you want:
xvals = {1, 2}
yvals = {3, 4}
{Sequence ## #, f ## #} & /# Tuples[{xvals, yvals}]
Warning: 5^9==1953125. So you may with to use a Do loop and write directly to file instead of creating these lists. To illustrate:
fmt = StringTemplate["``,``,``"];
Do[Print[fmt[x, y, f[x, y]]], {x, xvals}, {y, yvals}]
You'll want to replace Print with WriteLine.
Related
I made a very simple Octave script
a = [10e6, 11e6, 12e6];
b = [10, 11, 12];
plot(a, b, 'rd-')
which outputs the following graph.
Graph
Is it possible to set the numbering on the x-axis to engineering notation, rather than scientific, and have it display "10.5e+6, 11e+6, 11.5e+6" instead of "1.05e+7, 1.1e+7, 1.15+e7"?
While octave provides a 'short eng' formatting option, which does what you're asking for in terms of printing to the terminal, it does not appear to provide this functionality in plots or when formatting strings via sprintf.
Therefore you'll have to find a way to do this by yourself, with some creative string processing of the initial xticks, and substituting the plot's ticklabels accordingly. Thankfully it's not that hard :)
Using your example:
a = [10e6, 11e6, 12e6];
b = [10, 11, 12];
plot(a, b, 'rd-')
format short eng % display stdout in engineering format
TickLabels = disp( xticks ) % collect string as it would be displayed on the stdout
TickLabels = strsplit( TickLabels ) % tokenize at spaces
TickLabels = TickLabels( 2 : end - 1 ) % discard start and end empty tokens
TickLabels = regexprep( TickLabels, '\.0+e', 'e' ) % remove purely zero decimals using a regular expression
TickLabels = regexprep( TickLabels, '(\.[1-9]*)0+e', '$1e' ) % remove non-significant zeros in non-zero decimals using a regular expression
xticklabels( TickLabels ) % set the new ticklabels to the plot
format % reset short eng format back to default, if necessary
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'm trying to plot values from my geothermal heat pump log files to analyse it's performance. I tried with excel but it was to slow and not possible to get the plot type I wanted so I'm trying Octave instead. I have absolutely no experience with octave so please forgive my incompetence!
I've processed the .log files with open office calc to get into a decent delimited format. The first column is datetime with the format MM/DD/YY HH:MM:SS, in total there is 21 columns (but I only need 5) and one header line with a label, coma delimiter is '.' and delimiter is ','. The file can be downloaded here and the first 7 columns look like this:
02/19/2018 23:07:00,-0.7,47.5,42,47.3,52.1,1.5
I'm currently trying to plot this with demonstration 3 plotyy from here. Column 2, 3, 5 and 8 imports correctly so I'm figuring it's a problem with the datetime column 1. How can I get Octave to import column 1 correctly and use it as x axis in this plot?:
data=csvread('heatpump.csv');
clf;
hold on
t=data(:,1);
x=data(:,3);
y=data(:,5);
z=data(:,2);
o=data(:,8);
[hax, h1, h2] = plotyy (t, x, t, y);
[~, h3, h4] = plotyy (t, z, t, o);
set ([h3, h4], "linestyle", "--");
xlabel (hax(1), "Time");
title (hax(2), 'Heat pump analysis');
ylabel (hax(1), "Radiator and hot water temp");
ylabel (hax(2), "Outdoor temp and brine out");
There are many, many ways. Here I show you how to read the csv using csv2cell from the io package. I've tried to modify your existing code as less as sane. The first columns is used verbatim (well, I inserted a linebreak) to the plot. There is also a commented version which actually does the conversion and you could then use datetick. Btw, If you add google drive links it would be cool if you add direct links so someone can easily grab the csv or insert the url in the code as I've done, see below.
set (0, "defaultlinelinewidth", 2);
url = "https://drive.google.com/uc?export=download&id=1K_czefz-Wz4HPdvc7YqIqIupPwMi8a7r";
fn = "heatpump.csv";
if (! exist (fn, "file"))
urlwrite (url, fn);
endif
pkg load io
d = csv2cell (fn);
# convert to serial date
# (but you don't have if you want to keep the old format)
#t = datenum (d(2:end,1), "mm/dd/yyyy HH:MM:SS");
data = cell2mat (d(2:end,2:end));
clf;
hold on
t = 1:rows (data);
# Attention: the date/time column time was removed above, so the indizes are shifted
x = data(:,2);
y = data(:,4);
z = data(:,1);
o = data(:,7);
[hax, h1, h2] = plotyy (t, x, t, y);
[hax2, h3, h4] = plotyy (t, z, t, o);
grid on
#set ([h3, h4], "linestyle", "--");
xlabel (hax(1), "Time");
title (hax(2), 'Heat pump analysis');
ylabel (hax(1), "Radiator and hot water temp");
ylabel (hax(2), "Outdoor temp and brine out");
# use date as xtick
# extract them
date_time = d (get(hax2(1), "xtick"), 1);
# break them after the date part
date_time = strrep (date_time, " ", "\n");
# feed them back
set (hax, "xticklabel", date_time)
set (hax2, "xticklabel", date_time)
print ("-S1200,1000", "-F:10", "out.png")
I'm reading through the book, "SAS Functions by Example - Second Edition" and having trouble trying to understand a certain function due to the example and output they get.
Function: FINDC
Purpose: To locate a character that appears or does not appear within a string. With optional arguments, you can define the starting point for the search, set the direction of the search, ignore case or trailing blanks, or look for characters except the ones listed.
Syntax: FINDC(character-value, find-characters <,'modifiers'> <,start>)
Two of the modifiers are i and k:
i ignore case
k count only characters that are not in the list of find-characters
So now one of the examples has this:
Note: STRING1 = "Apples and Books"
FINDC(STRING1,"aple",'ki')
For the Output, they said it returns 1 because the position of "A" in Apple. However this is what confuses me, because I thought the k modifier says to find characters that are not in the find-characters list. So why is it searching for a when the letter "A", case-ignored, is in the find-characters list. To me, I feel like this example should output 6 for the "s" in Apples.
Is anyone able to help explain the k modifier to me any better, and why the output for this answer is 1 instead of 6?
Edit 1
Reading the SAS documentation online, I found this example which seems to contradict the book I'm reading:
Example 3: Searching for Characters and Using the K Modifier
This example searches a character string and returns the characters that do
not appear in the character list.
data _null_;
string = 'Hi, ho!';
charlist = 'hi';
j = 0;
do until (j = 0);
j = findc(string, charlist, "k", j+1);
if j = 0 then put +3 "That's all";
else do;
c = substr(string, j, 1);
put +3 j= c=;
end;
end;
run;
SAS writes the following output to the log:
j=1 c=H
j=3 c=,
j=4 c=
j=6 c=o
j=7 c=!
That's all
So, is the book wrong?
The book is wrong.
511 data _null_;
512 STRING1 = "Apples and Books" ;
513 x=FINDC(STRING1,"aple",'ki');
514 put x=;
515 if x then do;
516 ch=char(string1,x);
517 put ch=;
518 end;
519 run;
x=6
ch=s
given is a function f(a,b,x,y) in gnuplot, where we got a 3D-space with x,y,z (using splot).
Also given is a csv file (without any header) of the following structure:
2 4
1 9
6 7
...
Is there a way to read out all the values of the first column and assign them to the variable a? Implicitly it should create something like:
a = [2,1,6]
b = [4,9,7]
The idea is to plot the function f(a,b,x,y) having iterated for all a,b tuples.
I've read through other posts where I hoped it would be related to it such as e.g. Reading dataset value into a gnuplot variable (start of X series). However I could not make any progres.
Is there a way to go through all rows of a csv file with two columns, using the each column value of a row as the parameter of a function?
Say you have the following data file called data:
1 4
2 5
3 6
You can load the 1st and 2nd column values to variables a and b easily using an awk system call (you can also do this using plot preprocessing with gnuplot but it's more complicated that way):
a=system("awk '{print $1}' data")
b=system("awk '{print $2}' data")
f(a,b,x,y)=a*x+b*y # Example function
set yrange [-1:1]
set xrange [-1:1]
splot for [i in a] for [j in b] f(i,j,x,y)
This is a gnuplot-only solution without the need for a system call:
a=""
b=""
splot "data" u (a=sprintf(" %s %f", a, $1), b=sprintf(" %s %f", b, \
$2)):(1/0):(1/0) not, for [i in a] for [j in b] f(i,j,x,y)