I have been faced with the 'Index exceeds array bounds' while graphing.

Hey, I am trying to use the for code to plot a graph and it keeps saying that my index exceeds the array bounds. Not sure what to do to correct the loop. Thank you in advance.

 Tr=0.85:0.05:1; 
 MV= 0.15:0.02:1.75 
 Pr=zeros(length(Tr),81);
 Tr=0.85:0.05:1;
 for i= 1:length(Tr)   

 i
 MV= 0.15:0.02:1.75;
 [Pr(i,:)] = Isotherm(Tr(i)); 
hplot=semilogy(MV,Pr(i,:),'-')
hold on
set(hplot(i),'color', 'red', 'Marker','o')
set(hplot(i),'color', 'cyan')
set(hplot(i),'color', 'magenta')
set(hplot(i),'color', 'blue')
set(hplot,'linewidth', 1)
end

[madhan ravi]

Isotherm?

[Tamunopiriye Whyte]

it is at a different constant temperature for each time the iteration runs. so all that is changing is the molar volume and pressure.

[Tamunopiriye Whyte]

also that is just what I named my generic function.

 function [Pr] = Isotherm(Tr)
 MV= 0.15:0.02:1.75 %Range of molar volumes provided by the Brief.
 Pr= ((8*(Tr))./((8*(MV)) - 1) - (27./(64*(MV.^2))));
 end

[madhan ravi]

You can’t index a floating number to a variable

[Tamunopiriye Whyte]

Sorry not sure which is the floating number, new to MATLAB. Do you mind explaining what you mean by that.

[Tamunopiriye Whyte]

Also what would you suggest I should use to plot the graphs of the 4 different graphs to produce lines of different colors and markers. Thank you for your help.

Answer 1

[madhan ravi]

Tr=0.85:0.05:1; 
MV= 0.15:0.02:1.75 
Pr=zeros(length(Tr),81);
Tr=0.85:0.05:1;
MV= 0.15:0.02:1.75;
%Range of molar volumes provided by the Brief.
Pr=cell(1,4)
for i = 1:numel(Tr)
 Pr{i}= ((8.*(Tr(i)))./((8.*(MV)) - 1) - (27./(64.*(MV.^2))));
end;
hplot=semilogy(MV,Pr{1},'-')
hold on
hplot1=semilogy(MV,Pr{2},'-')
hplot2=semilogy(MV,Pr{3},'-')
hplot3=semilogy(MV,Pr{4},'-')

set(hplot,'color', 'red', 'Marker','o')
set(hplot1,'color', 'cyan')
set(hplot2,'color', 'magenta')
set(hplot3,'color', 'blue')

[Tamunopiriye Whyte]

wow! thanks

[madhan ravi]

Anytime :)