Way, way back in 1986, when I was developing the Method of Moments software that we are selling today , , I encountered (and overcame) many problems. One problem first became apparent when I was demonstrating prototype software at HP (now Agilent, soon to be Keysight Technologies) in Santa Rosa, one of my research sponsors. The results did not look so good. When we compared the results to measurement, the differences steadily increased as we went up in frequency. My funding from HP could be in jeopardy. Not good.