Class: NumRu::LinearCoordMapping

Inherits:
CoordMapping show all
Defined in:
lib/numru/gphys/coordmapping.rb

Instance Attribute Summary collapse

Attributes inherited from CoordMapping

#rank

Instance Method Summary collapse

Methods inherited from CoordMapping

#inversion_rigorous?, #map_grid

Constructor Details

#initialize(offset = nil, factor = nil) ⇒ LinearCoordMapping

Returns a new instance of LinearCoordMapping.



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# File 'lib/numru/gphys/coordmapping.rb', line 171

def initialize(offset=nil, factor=nil)

	 #< argument check & set rank, offset, factor >

	 if !offset && !factor
	    raise ArgumentError,"One of offset and factor must be specified"
	 elsif !factor
	    raise ArgumentError,"offset is not a NVector" if !offset.is_a?(NVector)
	    @rank = offset.length
	    @factor = NMatrix.float(@rank,@rank)
	    @factor.diagonal!(1)
	 else
	    raise ArgumentError,"factor is not a NMAtrix" if !factor.is_a?(NMatrix)
	    nx,ny = factor.shape
	    raise ArgumentError,"factor must be a square matrix" if nx != ny
	    @rank = nx
	    if offset
  raise ArgumentError,"offset is not a NVector" if !offset.is_a?(NVector)
  if offset.length != @rank
		  raise ArgumentError,"inconsistent dimensionarity between "+
 "offset #{offset.length} and factor #{factor.shape}"
  end
  @offset = offset
	    else
  @offset = NVector.float(@rank)
	    end
	    @factor = factor
	 end

	 #< other parameters >

	 @inversion_rigorous = true
	 @inv_factor = nil   # deferred until needed (might not be invertible)

end

Instance Attribute Details

#factor ⇒ Object (readonly)

Returns the value of attribute factor.



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# File 'lib/numru/gphys/coordmapping.rb', line 207

def factor
  @factor
end

#offset ⇒ Object (readonly)

Returns the value of attribute offset.



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# File 'lib/numru/gphys/coordmapping.rb', line 207

def offset
  @offset
end

Instance Method Details

#inverse ⇒ Object 



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# File 'lib/numru/gphys/coordmapping.rb', line 224

def inverse
	 __set_inv_factor if !@inv_factor
	 LinearCoordMapping.new( -@inv_factor*@offset, @inv_factor )
	 # Here, LinearCoordMapping.new is better than class.new,
   # since the constructor may change in subclasses.
end

#inverse_map(*args) ⇒ Object 



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# File 'lib/numru/gphys/coordmapping.rb', line 216

def inverse_map(*args)
	 __check_args_m(*args)
	 p = __to_NVector(*args)
	 __set_inv_factor if !@inv_factor
	 x = @inv_factor * ( p - @offset )
	 (0...@rank).collect{|i| x[i,false]}
end

#map(*args) ⇒ Object 



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# File 'lib/numru/gphys/coordmapping.rb', line 209

def map(*args)
	 __check_args_m(*args)
	 x = __to_NVector(*args)
	 p = @offset + @factor*x
	 (0...@rank).collect{|i| p[i,false]}
end