Floating point operation rate

The maximum vector capability occurs for matrix multiplication, for which the measured time on the CRAY-1 is twenty times faster than the best hand coded routines on the CDC 7600 or IBM 360/195. The maximum rate is circa. 135 Mflops (Millions of floating-point operations per second) for matrices that have dimensions which are a multiple of 64, the vector register size. The rate of computation for matrix multiplication is shown in figure 1 as a function of matrix size. 

Finally, most doubly or triply subscripted array operations can execute as a single vector instruction on the ASC. To demonstrate the hardware capabilities of the ASC,the vector dot product matrix multiplication instruction, which utilizes one of the most powerful pieces of hardware on the ASC, is compared to similar code on an IBM 360/91 and the CDC 7600 and Cyber 174. Table IV lists the Fortran pattern, which is recognized by the ASC compiler and collapsed into a single vector dot product instruction, the basic instructions required and the hardware speeds obtained when executing the same matrix operations on all four machines. Since many vector instructions in a CP pipe produce one result every clock cycle (80 nanoseconds), ordinary vector multiplications and additions (together) execute at the rate of 24 million floating point operations per second (MFLOPS). For the vector dot product instruction however, each output value produced represents a multiplication and an addition. Thus, vector dot product on the ASC attains a speed of 48 million floating point operations per second. 

The branch for the case when the squared pair separation is outside the table will inhibit vectorization. The last element of the table has been changed to zero and all occurrence outside the table are truncated to LMAX. The rest of the code, which is not executed on the VAX or CDC 7600, is executed here. It is often necessary on a vector machine to increase the total number of floating point operations to achieve vector rather than scalar processing. The MFLOP rates reported here are computed on the basis of the original number of floating point operations. The extra ones added to achieve vectorization are not included. 

The foam concentrate used with subsurface systems should be a fluoroprotein type for best results, although some AFFF foams are listed for substitutable application (because of their "fuel shedding" properties). The minimum foam solution rate should be 0.3 gpm/ft (12 Ipm/m ). The supply of foam liquid should be adequate to operate the system for 20 minutes. The foam injection point must be above the level of any residual water in the bottom of the tank. Subsurface foam application is not recommended for open or covered floating roof tanks or cone roof tanks with internal floating covers. 

Various types of valve arrangements are used for the valve-tray towers. Some of these are liltable disk-type valves which come as a cap with each riser. As the vapor rate increases, the valve lifts to provide a larger opening until it reaches a limit point which still directs the vapors horizontally into the liquid. Float-valve trays are designed to operate on the same principle as the liltable disk-type valves except that a floating pivotal valve is used hi each cap. 

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