Array indices must be positive integers or logical values

I have a problem to develop my coding. Here is my coding:

Mag=(6.5:0.1:9.5);

beta = bvalue * log(10);

MomentRate = (SM * 1e9)*(A*1e6)*(S/1000); MR=MomentRate;

for i = length(Mag)

N(i) = MR*(1.5-bvalue)*(1-exp(-beta*(M-Mag(i))))/(bv*Mo*exp(-beta(M-Mag(i))));

end

The problem is Array indices must be positive integers or logical values.

Let me how to solve my problem.

Thank you

Muktaf

[Ankit]

could you please post the complete code?

bvalue is missing.

Answer 1

[Adam]

for i = length(Mag)

doesn't make sense as this will just evaluate to a scalar. I don't see how this would be the source of your error, but it clearly isn't correct. I assume you want

for i = 1:numel(Mag)

Using numel or size with a relevant argument is generally better than using length, but the 1: part is the main change.

As to the error in question, using the debugger is the simplest way to find these.

    beta( M-Mag(i) )

looks like the source of the error though. This will likely not evaluate to an integer to index into beta, though I don't know what M is.

Also, the parenthesis are un-necessary in

Mag=(6.5:0.1:9.5);

Answer 2

[madhan ravi]

beta Operator missing here ( M

Note: Don’t name a variable beta because there is an inbuilt function named beta(). Preallocate N. The loop iterator should run from 1:length(...) (but I prefer numel() over length). Likely the loop is not necessary.

[madhan ravi]

Without loop it’s simply:

N = MR*(1.5-bvalue)*(1-exp(-Beta*(M-Mag)))./(bv*Mo*exp(-Beta operator missing here (M-Mag)));

[Skydriver]

Thank you it works now

Answer 3

[Skydriver]

Here my complete coding

S = 10; %S=Slip;

A = 2000; %A=Area;

SM = 30; %SM=Shear_Modulus;

bv = 0.8; %bv=bvalue;

M = 9.5; %M=Mmax;

m = 6.5; %m=Mmin;

bw = 0.1; %bw=bwith;

Mo = 2e23; %Mo=MoMax;

Mag=(6.5:0.1:9.5);

beta = bvalue * log(10);

MomentRate = (SM * 1e9)*(A*1e6)*(S/1000); MR=MomentRate;

for i = 1:numel(Mag)

N(i) = MR*(1.5-bvalue)*(1-exp(-beta( M-Mag(i) )))/(bv*Mo*exp(-beta(M-Mag(i))));

end