Meron Library

The following is a listing of the entire contents of this library for IDL. Click on an individual procedure name to view its header and source code. This listing is a shortened form of the much longer entire library help file. This may be handy for text searchs, be beware that some of these are huge and may take a long time to load or even crash your browser.

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List of Routines

• ABGRAD Calculates the absolute value of the gradient of a function represented as an array of values. Works for 1-7 dimensions.
• ARC Draws a circular arc in the currently defined plot area. DATA coordinates are used. The method of drawing depends on the number of
• ARREQ Compares arrays for equality. The arrays qualify as equal if: 1) They are of the same general type (num., char., or struct.). 2) Number of dimensions is the same. 3) Size of each dimension is the same. 4) Respective elements are equal.
• ARRLOC Converts array indices from expanded (multi dimensional) form to contracted (one dimensional) form and vice versa.
• ARRO. Draws an arrow in the current plot area, from the FROM to the TO location. DATA coordinates are used, unless one of the keywords /DEVICE or /NORMAL is set.
• ASP_CORR Corrects the aspect ratio of a 2-dimensional shape, in order to make up for for different scaling in the x and y dimensions.
• BESELK Calculates an approximation to Bessel K functions or their integrals.
• BOX Creates an empty plot area, with boundaries defined by XLIMS and YLIMS.
• CAST Generalized type casting. Converts variables whose type code is out of the range [LOW,HIGH] into this range.
• CHEBYSHEV_POL Calculates Chebyshev polynomials Tn and associated functions.
• CIRCLE Draws a circle, around CENTER, with radius given by RADIUS, X_RADIUS, or Y_RADIUS. The drawing is done in the currently defined plot area. One and ONLY ONE of the three radius values MUST be provided. RADIUS and X_RADIUS are equivalent. DATA coordinates are used unless one of the keywords /DEVICE or /NORMAL is set. The circle is drawn so as to appear visually as a circle, regardless of the coordinates used.
• CONFRAC Performs continued fraction evaluation.
• CONSTANTS Creates or updates a system variable named !PCON. !PCON is a structure the fields of which contain values of physical constants as follows:
• COO_CONV Transforms values between the coordinate systems supported by IDL. Allowed coord systems are DATA, DEVICE (only for X, Y axes) and NORMAL. Functionally similar to the IDL function CONVERT_COORD, COO_CONV is maintained for historical reasons.
• COSANGLE Finds the Cosine of the angle between two vectors.
• DEFAULT Provides an automatic default value for nondefined parameters.
• DEGLITCH Replaces exceptional array elements by the average of their neighbors.
• DIAGOARR Creates a diagonal square matrix with the elements of a given vector on
• DIAGOVEC Extracts the diagonal of a square matrix as a vector.
• ELLIPSE Draws an ellipse, around CENTER, with radii given by RADII, optionally rotating it by angle ROT. The drawing is done in the currently defined plot area. DATA coordinate system is assumed unless specified otherwise by one of the keywords /DEVICE or /NORMAL.
• ERRBARS Overplots error bars over an existing plot. More general than the library routines ERRPLOT and PLOTERR, since it allows to independently vary both X and Y errors, and allows for nonsymmetric error bars.
• EXTEND_ARRAY Extends an array to a larger size, filling the blanks according to keyword specifications.
• EXTREMA Finding all local minima and maxima in a vector.
• FPU_FIX Clears Floating Point Underflow errors, setting the offending values to
• FRESNEL_INT Calculates the Fresnel Integrals, C(x) or S(X).
• HEAD Displays the beginning ("head") or, optionally, a selected part of an
• HOW_MANY Called with up to 8 keyword parameters, HOW_MANY checks how many and which of the corresponding variables are defined and (optionally) within given type limits.
• INTEG Integrates a function provided as an array of points.
• ISNUM Checks whether the input is a number.
• LABELS Multiple XYOUTS interface.
• LAPLACIAN Calculates the Laplacian of a function represented as an array of values. Works for 1-7 dimensions.
• LEGENDRE_POL Calculates Legendre polynomials Pl and associated polynomials Plm.
• LINCROSS Finds the crossing point of two line segments or lines, in 2D.
• MAKE_GRID Generates a 1-6 dimensional grid of points within a specified range.
• M_ABS Calculates absolute values. A temporary fix needed since the IDL ABS function fails with very large or very small complex numbers.
• M_CONVOL Calculates the convolution of two functions represented by arrays.
• M_ERRORF Calculates the error function. Replacement for the IDL ERRORF function which accepts only real input.
• M_GAMMA Calculates the gamma function. Replacement for the IDL GAMMA function which accepts only real input.
• M_IGAMMA Calculates the incomplete gamma function. Replacement for the IDL IGAMMA function which accepts only real input.
• M_IMAGINARY Returns imaginary values.
• M_LINFIT Linear fitting with an arbitrary number of parameters.
• M_LNGAMMA Calculates the natural log of the gamma function. Replacement for the IDL LNGAMMA function which accepts only real input.
• M_NERFC Calculates A renormalized complementary error function.
• M_REAL Returns real values.
• M_SMOOTH Non broadening data smoothing.
• NATAN Calculates the function /int{(1 + x^2)^(-n-1)}, or, optionally, /int{(1 - x^2)^(-n-1)}
• NEIGHBORS Finding the nearest neighbors of an array element.
• NOISE Adds Gaussian or Poissonian noise to data.
• ONE_OF Called with up to 8 variables V_0 through V_7 , ONE_OF checks which variable is defined (only one is supposed to be).
• OUTPUT Generic output interface. Allows sending the results of virtually any IDL command or file to any predefined hard copy device. In detail, OUTPUT executes the provided command, writes the output to a file and sends the file to a printout que. Currently a VMS routine only.
• PARTOT Array summation.
• PLOTOT Plots multiple data sets on a single plot.
• PLOT_VER2 Draws 2 plots, vertically spaced, with a possibility of multiple curves
• PLVAR_KEEP Saves or restores the values of system variables.
• POLEVAL Evaluates a polynomial function according to the formula: F = c(0) + c(1)*X + ... + c(n)*X^N Similar to the library routine POLY. The difference is that when the keyword QUOTIENT is used, the routine returns, in QCOEF, the values of the coefficients of the quotient polynomial. In other words, given the coefficients of a polynomial P, and a value Xc, the function returns the value P(Xc), and in QCOEF are returned the coefficients of the polynomial Q(X) = P(X)/(X - Xc). Note that unless P(Xc) is 0, the division has a remainder.
• PRINUMS Calculates a table of prime numbers in the range NLO - NHI.
• RANDISC Generates a set of discretely distributed random numbers.
• RASCII Reads data from an ASCII file into an array. It is assumed that the file contains columns of numbers, with the same number of entries in each row. The numbers may be separated by commas, spaces and/or tabs. The file may contain a header. The first line in which the first non-blank character is one of ".+-0123456789" will be considered the beginning of the data. Text lines imbedded in the data are skipped.
• RECTAN Draws a rectangle between the limits specified by XLIMS and YLIMS. The drawing is done in the currently defined plot area. DATA coordinate system is assumed unless specified otherwise by one of the keywords /DEVICE or /NORMAL.
• ROMBERG Performs high precision numerical integration.
• ROOT Finds roots of real functions.
• SEQLIM Estimates limits of infinite sequences.
• SERIES_SUM Estimates sums of infinite series.
• SHAPE_AREA Calculates the area enclosed by a 2-dimensional shape.
• SHAPE_CLOSE Closes the shape, i.e. appends the first point to the end of the shape, unless the shape is already closed in which case nothing happens.
• SHAPE_COCON Converts 2 or 3 dimensional shapes from the FROM to the TO coordinate system. Allowed systems are DATA, DEVICE (only for 2-dim shapes) and NORMAL. In principle identical to the system routine CONVERT_COORD, SHAPE_COCON is maintained for historical reasons.
• SHAPE_EDGE Modifies a SHAPE (see SHAPE_VER for a definition) by cutting it along a straight edge.
• SHAPE_TRANS Performs a geometrical transformation of an arbitrary 2_dim shape. The transformation may include (in order): 1) Magnification by MAG. If MAG is a 2-dim vector, X and Y coordinates are magnified by MAG(0) and MAG(1) respectively. If FLIP is set, the magnification will include inversion in the X or Y axis, according to the value of FLIP. 2) Rotation by the angle ANG. 3) Translation by ROFF.
• SHAPE_VER Checks whether SHAPE is a proper shape, i.e. a (2,*) or (3,*) , numeric non-complex array.
• SHUFFLE Randomizes an array.
• SIGN Gives the sign of X, i.e. 1 for positive, -1 for negative, 0 for 0.
• SOLVE_LINSYS Solves the system of linear equations ARR*X = RHS
• SORPURGE Similar to the SORT function, but ignores repeated values of elements.
• SPLINROOT Finds roots of function provided as a set of spline coefficients.
• SPLINT Integrates a function provided as a set of spline coefficients.
• SPLIN_COEFFS Calculates cubic splines coefficients which are intended to be used by the supplementary function SPLIN_EVAL. The combination of SPLIN_COEFFS and SPLIN_EVAL is more efficient than the library function SPLINE when repeated interpolations based on the same data set are performed.
• SPLIN_EVAL Cubic spline evaluation using spline coefficients supplied by the supplementary function SPLIN_COEFFS. The combination of SPLIN_COEFFS and SPLIN_EVAL is more efficient than the library function SPLINE when repeated interpolations based on the same data set are performed.
• SP_BESELJ Calculates spherical Bessel functions of the first kind, j_n(x).
• SP_BESELY Calculates spherical Bessel functions of the first kind, y_n(x).
• SQUARE Draws a SQUARE, based on a length of a side and a given location of a corner. The square is drawn so as to appear visually as a square, even if the lengths of the sides in DATA coordinates differ. The drawing is done in the currently defined plot area. DATA coordinates are used unless one of the keywords /DEVICE or /NORMAL is set.
• SQUNEXP Calculates a "flattened" exponent. See definition below.
• SQUNORM Calculates a "flattened" Gaussian. See definition below.
• STREQ Compares for equality the first LEN characters of STR1, STR2. If LEN is 0, or absent, the whole strings are compared.
• STRMATCH Compares the string STR with the strings in the array LIST. Comparison is done for the first LEN characters, or all of them if LEN is 0. If a match is found, STR is replaced by the full string from the list (or if the keyword /ALL is set, by an array containing all the matching
• STRPARSE Parses the string LINE using the characters in DELIM as delimiters. Puts individual pieces into consecutive locations in LIST.
• TABULATE Accepts data in form of a set (up to 8) one dimensional arrays and prints it out as a table.
• TAIL Displays the ending ("tail") or, optionally, a selected part of an
• TOLER Establishes numerical tolerance value for numerical procedures.
• TYPE Finds the type class of a variable.
• UNIVEC Normalizes a vector.
• VINP Finds the scalar product of two vectors.
• VNORM Finds the norm of a vector.
• VOUP Finds the outer product of two vectors.
• WASCII Writes an array into an ASCII file.
• WHERINSTRUCT Finding fields within a structure.