TITLE="sample"
VARIABLES="x","y","u","v","c","p"
ZONE I=200,j=500,f=point
5.400000e-001  1.725000e+000  -4.310935e-001 1.377267e-001 1.000157e+000  2.902895e+000
5.350000e-001  1.735000e+000  -4.228539e-001 1.324792e-001 1.000015e+000  2.893465e+000
9.150000e-001  1.425000e+000  -4.668409e-001 5.993293e-001 -2.144223e-004  2.991053e+000
9.400000e-001  1.415000e+000  -4.663431e-001 6.105488e-001 -4.411785e-004  2.991502e+000
9.500000e-001  1.835000e+000  -3.079936e-002 3.472100e-001 9.998619e-001  2.898153e+000
9.550000e-001  1.845000e+000  -2.692575e-002 3.344990e-001 9.999598e-001  2.886636e+000
9.750000e-001  1.435000e+000  -5.179061e-001 6.542616e-001 -1.823437e-004  2.992287e+000
...............

点的个数在变化中,但只能知道变化后点的个数,I,J该怎么确定?