* Example of how to speed up IGRAPH. GET FILE='c:\\program files\\spss\\employee data.sav'. * Round salary to nearest 10. COMPUTE salary=RND(salary/10)*10. AGGREGATE /OUTFILE=* /BREAK=salary /wgt = NU(salary). *The file employee data has 474 cases, By multiplying the wgt variable (the number of cases at each salary levels) by 2,000 we are creating a file of 948,000 cases. COMPUTE wgt=wgt*2000. WEIGHT BY wgt. GRAPH /HISTOGRAM=salary .