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HELP FOR: grcalc1
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CALLING SEQUENCE:  grcalc1 ( object, indexList );

      PARAMETERS:  object      - GRTensorII object name
                   indexList   - index list specifying a component

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SYNOPSIS:

- This function can be used to calculate a single component of
  a tensor. 

- This is useful when the metric is sufficiently complicated
  that certain components of tensors can not be calculated without
  running into a MapleV `Object Too Large' error. Using grcalc1(), at least
  some information may be extracted by avoiding such components and
  calculating the other components individually.

- The desired component is specified by a list which gives the value
  of each tensor index as either a number or coordinate name.
  For example, if we are considering a spacetime with coordinates
  (r,theta,phi,t) the following equivalent lists could be used to
  indicate the (r,r,phi,t) component of the Riemann tensor:

                 [1,1,3,4]    or   [r,r,phi,t]

- Note that since only one component has been calculated, GRTensorII 
  will not recognize the object as calculated and so the result of the
  calculation cannot be displayed with grdisplay() (grcomponent() must
  be used). Calculation of all components of an object can be
  done with grcalc().

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EXAMPLES:

> qload ( schw ):

> grcalc1 ( Chr(dn,dn,up), [theta,theta,r] ):

Calculated detg for schw. (0.020000 sec.) 
Calculated g(up,up) for schw. (0.060000 sec.) 
Calculated g(dn,dn,pdn) for schw. (0.060000 sec.) 
Calculated Chr(dn,dn,dn) for schw. (0.060000 sec.) 
Calculated the [theta, theta, r] component of Chr(dn,dn,up) for schw.

> grcomponent ( Chr(dn,dn,up), [theta,theta,r] );

                                   - r + 2 m

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SEE ALSO: grcalc, grcomponent.
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