# alm2spec

Evaluate angular power spectral density

## Contents

- Syntax
- Input Arguments
- Return Arguments
- Description
- Example
- See also

## Syntax

    cL = alm2spec(alm)
    cL = alm2spec(alm, lMax)

## Input Arguments

alm real valued coefficients lMax max order of harmonic to calculate (default 20)

## Return Arguments

    cL      angular power spectrum

## Description

The angular power spectrum of the function f,

are the coefficients

## Example

Find power spectrum coefficients of dummy data set

    nSide = 2^4;
    nPix = nSide2nPix(nSide);
    pix = 3*(ylm(nSide,4,2) + ylm(nSide,4,1)) + sqrt(17)*ylm(nSide,8,-4) ...
      + rand(1,nPix);
    lMax = 10;
    alm = pix2alm(pix,lMax);
    cL = alm2spec(alm,lMax);
    stem(0:lMax,cL);

## See also

pix2alm, alm2pix

Copyright 2010-2011 Lee Samuel Finn. Terms of Use.