If function for matrix

hi there

i need to do this if function

if a <= b

    c = 1

else

    c = realmin

but, a and b is a matrix (30x30)

and apparently i got only 1 value of c,

i want a the if function compare every cell of matrix a and b,

and gives me value in 30x30 matrix too

please help, thank you

Answer 1

[madhan ravi]

idx=a<b

c(idx)=1

c(~idx)=realmin

[Antoni Ho]

it is actually works, but what is this idx actually? can i use it again on different variables?

[madhan ravi]

use it is a logical index which stores the index of the variables when the condition is satisfied , yes you can use it on different variables also changing the variable name in the condition. see logical indexing for further explanation

[Antoni Ho]

thank you for your help

so the code is like this?

idx=a<b

c(idx)=1

c(~idx)=realmin

idx=d<e

f(idx)=1

f(~idx)=realmin

[madhan ravi]

Anytime :),yes exactly , if it worked make sure to accept the answer

[Antoni Ho]

now i got this problem, i have (30x8 matrix). and the result i got from idx is 1 x 240 matrix. do you know how to make them 30 x 8 (i dont use normal matrix operation but elementwise only operation)

madhan ravi's reply : post a separate question by providing all the necessary details

[Torsten]

c = ones(size(a))
idx = a>=b
c(idx) = realmin

[madhan ravi]

+1 @Torsten - an absolut genius!!

[Antoni Ho]

wow @Torsten real genius, it worked