IDL Reference Guide: Procedures and Functions

DERIVSIG

The DERIVSIG function computes the standard deviation of a derivative as found by the DERIV function, using the input variables of DERIV and the standard deviations of those input variables.

Syntax

Result = DERIVSIG( [X, Y, Sig_x,] Sig_y )

Return Value

Returns the standard deviation of a derivative as found by the DERIV function.

Arguments

X

Differentiate with respect to this variable. If omitted, unit spacing for Y (i.e., Xi = i) is assumed.

Y

The variable to be differentiated. Omit if X is omitted.

Sigx

The standard deviation of X (either vector or constant). Use "0.0" if the abscissa is exact; omit if X is omitted.

Sigy

The standard deviation of Y. Sigy must be a vector if the other arguments are omitted, but may be either a vector or a constant if X, Y, and Sigx are supplied.

Keywords

None.

Version History

See Also

DERIV

  IDL Online Help (March 06, 2007)