`Macros to model downward pull of anchors using negative ground points.

`Define anchor
MACRO Anchor `%1=anchor number, %2,%3,%4=attachment pt, %5=initial force, %6=df/dh
 variable c
 set c=%6 times %6 div 4 div %5
 set c={weight} div {c}
 set c=sqrt {c}
 GROUND "Anchor %1 downward force" -%5, %2,%3,%4 /pen:,{c}
/


`--------------------------------------

MACRO AnchTest

 read tlp.gf
 depth = 55
 vcg = 60
 solve weight, lcg

 variable w
 set w={weight} minus 400
 weight {w}

 `Define anchors
 `     anch #  long    trans  vert  f0   df/dh
  .Anchor  1 , 50.0 ,  50.0p , 50 , 100 ,  10
  .Anchor  2 , 50.0 ,  50.0s , 50 , 100 ,  10
  .Anchor  3 ,-50.0 ,  50.0p , 50 , 100 ,  10
  .Anchor  4 ,-50.0 ,  50.0s , 50 , 100 ,  10

 `Solve for equilibrium condition:
 SOLVE
 STATUS GHS  `Produce status report
/

.AnchTest