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Institut für Astronomie und Astrophysik

Abteilung Astronomie

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Table of Contents



Introduction

This directory contains IDL mathematics and statistics procedures thought to be of interest in astronomy. Twelve of the procedures, are adapted from algorithms in "Numerical Recipes 2nd Edition" by Press, Flannery,Teukolsky, and Vetterling (1992, Cambridge University Press). These procedures are marked below with an "NR"

The FORTRAN procedure names in "Numerical Recipes" are limited to 6 characters, and in some cases (e.g. MINF_PARABOLIC for BRENT) we have chosen more descriptive names for the equivalent IDL procedure.

Additional IDL mathematics and statistics procedures developed by Henry Freudenreich (Hughes STX) are available in the contrib/freudenreich directory. These include procedures for LOWESS smoothing, robust fitting, bootstrap errors, and fitting to a plane.


Index of Subroutines

ASINH Return the inverse hyperbolic sine of the argument
AVG Return the average value of an array, or 1 dimension of an array
CIC Interpolate an irregularly sampled field using Cloud in Cell method
CSPLINE Function to evaluate a natural cubic spline at specified data points
FITEXY Best straight-line fit to data with errors in both coordinates
FLEGENDRE Compute the first M terms in a Legendre polynomial expansion.
GAUSSIAN Compute the 1-d Gaussian function and optionally the derivative
HERMITE To compute Hermite spline interpolation of a tabulated function.
KSONE Compute the one-sided Kolmogorov-Smirnov statistic
KSTWO Return the two-sided Kolmogorov-Smirnov statistic
KUIPERONE Compute the one-sided Kuiper statistic (invariant Kolmogorov-Smirnov)
KUIPERTWO Compute the two-sided Kuiper statistic (invariant Kolmogorov-Smirnov)
LINTERP Linearly interpolate tabulated 1-d data from one grid to a new one.
MEANCLIP Computes an iteratively sigma-clipped mean on a data set
MINF_BRACKET Bracket a local minimum of a 1-D function with 3 points,
MINF_CONJ_GRAD Find the local minimum of a scalar function using conjugate gradient
MINF_PARABOL_D Minimize a function using a modified Brent's method with derivatives
MINF_PARABOLIC Minimize a function using Brent's method with parabolic interpolation
NGP Interpolate an irregularly sampled field using Nearest Grid Point
PCA Carry out a Principal Components Analysis (Karhunen-Loeve Transform)
PENT Return the information entropy of a time series
POIDEV Generate a Poisson random deviate
POLINT Interpolate a set of N points by fitting a polynomial of degree N-1
POLY_SMOOTH Apply a least-squares (Savitzky-Golay) polynomial smoothing filter
POLYLEG Evaluate a Legendre polynomial with specified coefficients.
PROB_KS Return the significance of the Kolmogoroff-Smirnov statistic
PROB_KUIPER Return the significance of the Kuiper statistic
QSIMP Integrate using Simpson's rule to specified accuracy.
QTRAP Integrate using trapezoidal rule to specified accuracy.
QUADTERP Quadratic interpolation of X,Y vectors onto a new X grid
RANDOMP Generates an array of random numbers distributed as a power law.
SIXLIN Compute linear regression coefficients by six different methods.
SPLINE_SMOOTH Compute a cubic smoothing spline to (weighted) data
TABINV To find the effective index of a function value in an ordered vector.
TRAPZD Compute the nth stage of refinement of an extended trapezoidal rule.
TSC Interpolate an irregularly sampled field using a Triangular Shaped Cloud
TSUM Trapezoidal summation of the area under a curve.
ZBRENT Find the zero of a 1-D function up to specified tolerance.
Last modified by pro2html on 2008 November 09 at 04:12 UTC

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Jörn Wilms (wilms@astro.uni-tuebingen.de)
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