CODEWITHSUNDEEP
javamath
Rikkin
Rikkin

Reputation: 509

Using Math.pow() function

I'm trying to make a program in Java to calculate the formula for the Ricker wavelet:

enter image description here

But the results are not matching to the real ones.

This is what I'm using:

private static double rickerWavelet(double t, double f){

   double p = (Math.pow(Math.PI, 2))*(Math.pow(f, 2))*(Math.pow(t, 2));

   double lnRicker = 1 - (2 * p) * Math.exp(-p);

   return lnRicker;
}

Am I using the Math functions wrongly?

Upvotes: 7

Views: 6139

Answers (3)

Stephen C
Stephen C

Reputation: 719551

I'd just like to add that Math.pow(x, 2) can be written more simply (and possibly more accurately and more efficiently) as x * x ... for any variable or constant x.

Upvotes: 3

Jimmy
Jimmy

Reputation: 47

Look at your executing equation if you know about BODMAS method:

You should do: (1-(2*p))* Math.exp(-p);

I just changed your equation by inserting round brackets around 1-2*p..

Upvotes: 2

AakashM
AakashM

Reputation: 63378

To match the formula,

double lnRicker = 1 - (2 * p) * Math.exp(-p);

needs to be

double lnRicker = (1 - (2 * p)) * Math.exp(-p);

Since * has higher operator precedence than -, in your expression the multiplication of (2 * p) with Math.exp(-p) will be done first, which is not what you want.

Upvotes: 11

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