Read spherical harmonic coefficients from an ascii-formatted file.

## Usage

call SHRead (`filename`

, `cilm`

, `lmax`

, `skip`

, `header`

, `error`

, `exitstatus`

)

## Parameters

`filename`

: input, character(:)- The filename of the ascii file containing the spherical harmonic coefficients.
`cilm`

: output, real*8, dimension (2,`lmax`

+1,`lmax`

+1)- The spherical harmonic coefficients contained in
`filename`

. `lmax`

: output, integer- The maximum spherical harmonic degree of
`cilm`

. This is the minimum of the maximum spherical harmonic degree of`filename`

and the dimension of`cilm`

-1. `skip`

: input, optional, integer- The number of lines to skip before parsing
`filename`

. `header`

: output, optional, real*8 dimension (`n`

)- A vector containing the first
`n`

numbers in the first line of the file (following any skipped lines). `error`

: output, optional, real*8 dimension (2,`lmax`

+1,`lmax`

+1)- The errors corresponding to the spherical harmonic coefficients
`cilm`

. `exitstatus`

: output, optional, integer- If present, instead of executing a STOP when an error is encountered, the variable exitstatus will be returned describing the error. 0 = No errors; 1 = Improper dimensions of input array; 2 = Improper bounds for input variable; 3 = Error allocating memory; 4 = File IO error.

## Description

`SHRead`

will read spherical harmonic coefficients from an ascii-formatted file into an array `cilm`

. The maximum spherical harmonic degree that is read is determined by the minimum of the dimension of the input array `cilm`

-1 and the maximum degree of the coefficients in the file. If the optional array `skip`

is specified, parsing of the file will commence after the first `skip`

lines. If the optional array `header`

is specified, then the first `n`

elements after the skipped lines will be output, where `n`

is the length of the array `header`

.

The spherical harmonic coefficients in the file are assumed to be ordered by increasing degree `l`

and angular order `m`

according to the format

`l, m, cilm(1,l+1,m+1), cilm(2,l+1,m+1)`

The actual delimeters (commas, spaces, or tabs) are unimportant. If the optional array `error`

is specified, then the error for each coefficient will be read according to the format

`l, m, cilm(1,l+1,m+1), cilm(2,l+1,m+1), error(1,l+1,m+1), error(2,l+1,m+1)`

The ordering of the file is explcitly given by

`l, 0 / l, 1 / l, 2 /l, ... / l, m / l+1, 0 / l+1, 1 / ...`

The first spherical harmonic degree of the filename does not have to be 0; this is determined from the first element after the `skip`

and `header`

lines.