SmartSpice Tips: Memory Usage, .MODIF & .ALTER, Non-convergence

Introduction

When you run a long simulation time analysis the evaluated time points are normally all held in memory until the end time is reached. All the data is then written out to the output rawfile. This means a large amount of system memory can be used up and also has to be tracked. If in the input deck the line “.OPTIONS RAWPTS=300 POST” is included then as soon as the maximum number of points is reached given by “RAWPTS=300” then all the vector data is saved to the raw data output file and the memory is free to be re-used. In this way the output rawfile is incrementally increased in size every time this limit is reached. The memory required by the simulation run is therefore reduced, and with less memory to manage, the simulation is run faster. This is particularly useful on the PC platform where some of the memory is required for the operating system and RAM size is less than 1Gig.