File: yorick.py

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## Automatically adapted for scipy Oct 31, 2005 by

# $Id: yorick.py 1698 2006-03-14 23:12:10Z cookedm $
# Copyright (c) 1996, 1997, The Regents of the University of California.
# All rights reserved.  See Legal.htm for full text and disclaimer.
from scipy import *
import os
import time
from shapetest import *
"""
   The yorick module supplies Python versions of some common
   yorick functions: zcen_, dif_, maxelt_, minelt_, rem_0_,
   avg_, timer_, timer_print.
"""

_ZcenError = "ZcenError"

def zcen_ (x, i = 0) :

    """
    zcen_(x, i) does the same thing as in Yorick: x(...,zcen,...)
    where zcen is the ith subscript. (works for up to 5 dimensions).
    Namely, the elements along the ith dimension of x are replaced
    by the averages of adjacent pairs, and the dimension decreases
    by one. Remember that Python sunscripts are counted from 0.
    """

    if is_scalar (x) :
        raise _ZcenError, "zcen_ must be called with an array."
    dims = shape (x)
    ndims = len (dims)
    if i < 0 or i > ndims - 1 :
        raise _ZcenError, "i <" + `i+1` + \
           "> is out of the range of x's dimensions<" + `ndims` +"."
    if i == 0 :
        newx = (x [0:dims [0]-1] + x [1:dims [0]]) /2.0
    elif i == 1 :
        newx = (x [:, 0:dims [1]-1] + x[:, 1:dims [1]]) / 2.0
    elif i == 2 :
        newx = (x [:, :, 0:dims [2]-1] + x[:, :, 1:dims [2]]) / 2.0
    elif i == 3 :
        newx = (x [:, :, :, 0:dims [3]-1] + x[:, :, :, 1:dims [3]]) / 2.0
    elif i == 4 :
        newx = (x [:, :, :, :, 0:dims [4]-1] + \
                x [:, :, :, :, 0:dims [4]]) / 2.0

    return newx

_DifError = "DifError"

def dif_ (x, i = 0) :

    """
    dif_(x, i) does the same thing as in Yorick: x(...,dif_,...)
    where dif_ is the ith subscript. (works for up to 5 dimensions).
    Namely, the elements along the ith dimension of x are replaced
    by the differences of adjacent pairs, and the dimension decreases
    by one. Remember that Python sunscripts are counted from 0.
    """

    if is_scalar (x) :
        raise _DifError, "dif_ must be called with an array."
    dims = shape (x)
    ndims = len (dims)
    if i < 0 or i > ndims - 1 :
        raise _DifError, "i <" + `i+1` + \
           "> is out of the range of x's dimensions <" + `ndims` +">."
    if i == 0 :
        newx = x [1:dims [0]] - x [0:dims [0] - 1]
    elif i == 1 :
        newx = x [:, 1:dims [1]] - x[:, 0:dims [1] - 1]
    elif i == 2 :
        newx = x [:, :, 1:dims [2]] - x [:, :, 0:dims [2] - 1]
    elif i == 3 :
        newx = x [:, :, :, 1:dims [3]] - x [:, :, :, 0:dims [3] - 1]
    elif i == 4 :
        newx = x [:, :, :, :, 1:dims [4]] - x [:, :, :, :, 0:dims [4] - 1]
    return newx

def maxelt_ (*x) :

    """
    maxelt_ accepts a sequence of one or more possible multi-dimensional
    objects and computes their maximum. In principle these can be of
    arbitrary complexity, since the routine recurses.
    """

    if len (x) == 0 :
        return None
    elif len (x) == 1 :
        z = x [0]
        if is_scalar (z) :
            return z
        if len (shape (z)) >= 1 :
            zz = array (z)
            return maximum.reduce (ravel (zz))
    else :
        maxelt = maxelt_ (x [0])
        for i in range (1, len (x)) :
            maxelt = max (maxelt, maxelt_ (x [i]))
        return maxelt

def minelt_ (*x) :

    """
    minelt_ accepts a sequence of one or more possible multi-dimensional
    objects and computes their minimum. In principle these can be of
    arbitrary complexity, since the routine recurses.
    """

    if len (x) == 0 :
        return None
    elif len (x) == 1 :
        z = x [0]
        if is_scalar (z) :
            return z
        if len (shape (z)) >= 1 :
            zz = array (z)
            return minimum.reduce (ravel (zz))
    else :
        minelt = minelt_ (x [0])
        for i in range (1, len (x)) :
            minelt = min (minelt, minelt_ (x [i]))
        return minelt

def rem_0_ (z) :

    """
    rem_0_ (z) goes through array z and replaces any zero
    elements with 1.e-35. Assumes z has one or two dimensions.
    """

    if len (shape (z)) == 1 :
        for i in range (len (z)) :
            z [i] = z [i] + (z [i] == 0.0) * 1.e-35
    elif len (shape (z)) == 2 :
        (k, l) = shape (z)
        for i in range (k) :
            for j in range (l) :
                z [i] [j] = z [i] [j] + (z [i] [j] == 0.0) * 1.e-35

def avg_ (z) :

    """
    avg_ (z) returns the average of all elements of its array
    argument.
    """

    zz = array (z, copy = 1 )
    return add.reduce (ravel (zz)) / len (ravel (zz))

def sign_ (x) :
    if x >= 0 :
        return (1)
    else :
        return (- 1)

def timer_ (elapsed, *split) :

    """
    timer (elapsed) returns a triple consisting of the times
    [cpu, system, wall].
    timer (elapsed, split) returns a sequence whose first element
    is [cpu, system, wall] and whose second element is the
    sum of split and the difference between ththe new and old values
    of 'elapsed.'
    """

    stime = os.times ( )
    wtime = time.time ( )
    retval = array ( [stime [0], stime [1], wtime], Float )
    if len (split) == 0 :
        return retval
    else :
        return [retval, split [0] + retval - elapsed]

def timer_print (label, split, *other_args) :

    """
    timer_print (label1, split1 [,label2, split2, ...]) prints
    out a timing summary for splits accumulated by timer_.
    """

    print label, split
    i = 0
    while i < len (other_args) :
        print other_args [i], other_args [i + 1]
        i = i + 2