[dennou-ruby:000104] NMDArray revised

[Takeshi Horinouchi <horinout@xxxxxx>]

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  ftp://dennou-t.ms.u-tokyo.ac.jp/arch/davis/ex/1999-09-08-horinout/

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  nmd_array-19991004.tgz

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   where(a>0)
     a=a*b
   endwhere

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---
  def each_set!(&block)
    # Elementwise operation. Each element is replaced with the value
    # evaluated by the last statement in the block. The data substitution
    # is suppressed when the value is nil.
    # Note that the operation can be applied to selected elements by using
    # if conditioning (see examples).
    # This is a destructive method (with "!"); the object is modified
    # directly. Use each_set (without "!") to create another object to
    # return the result, leaving the original one intact.
    #
    # Usage: array.each_set!{block}
    # Example: array.each_set!{|x| x*3}     # multiply 3 to all elements
    #          array.each_set!{|x| x*3 if x>0}    #same but only when positive
    #          array.each_set!{|x| s=sin(x); x+s if(cos(x)>0.0)}
    #                       # last value (x+s) is substituted if the condition
    #                       # is satisfied. Here, s is a local variable
    #                       # only in the block ({} introduces a new scope).

    @xxxxxx do
      |i|
      eval = block.call(@xxxxxx[i])
      @xxxxxx[i]=eval if (eval != nil)
    end
  end

  def each_set(&block)
    out=self.dclone         # deep clone
    out.each_set!(&block)
    return out
  end
---
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% irb
irb(main):001:0> require "NMDArray"
nil
irb(main):002:0> a=NMDArray.indgen(3,2)
#<NMDArray: @xxxxxx=[3, 2], @xxxxxx=[0.0, 1.0, 2.0, 3.0, 4.0, 5.0], @xxxxxx=6, @xxxxxx=2>
irb(main):003:0> b=a.each_set{|x| x*3 if x>3}
#<NMDArray: @xxxxxx=[3, 2], @xxxxxx=[0.0, 1.0, 2.0, 3.0, 12.0, 15.0], @xxxxxx=6, @xxxxxx=2>
irb(main):004:0> a.prt
[0.0, 1.0, 2.0,
3.0, 4.0, 5.0]
nil
irb(main):005:0> b.prt
[0.0, 1.0, 2.0,
3.0, 12.0, 15.0]
nil

---
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