vector equals to value in matrix

i have a vector, A=0.9997 and a matrix gg=(0.35:0.0001:2); when i try to run,= any(eq(A,gg)) or any(A==gg); to find if A is in gg it always returns it as zero even though it return one as it is part of the elements of gg .if i run any(eq(0.9997,gg)), it returns it as one. Is there any reason for this and how can i rectify this?

Answer 1

[M]

The three following expressions:

any(eq(A,gg))
any(A==gg)
any(eq(0.9997,gg))

are the same and equal to 1. What is your problem exactly?

[Nkenna Amadi]

yes but when i run the first two it returns ans = 0

[madhan ravi]

When I used the first two codes , my error message was matrix dimensions must agree, I think only it recognises numbers?

[Nkenna Amadi]

thats my problem because i have a the value of A changes as it is a loop, so i cant just put a number

[M]

You didn't say that the value of A changes in a loop. Look at Dennis' answer for more details.

Answer 2

[Dennis]

A=0.9997 and changing A in a loop are 2 different things.

This code will return 1.

gg=(0.35:0.0001:2);
A=0.9997;
any(A==gg)

This code wont, though A is 0.9997.

gg=(0.35:0.0001:2);
A=1.0997-0.1
any(A==gg)

The reason for this is that floating point numbers are not represented 100% accurate in binary form.

You can use abs(a-b)<tolerance to avoid this.

gg=(0.35:0.0001:2);
A=1.0997-0.1
any(abs((A-gg))<1e-10)

For more information on the topic please have a look here