BLAS/SRC/sdsdot.f(3)

💖 BLAS/SRC/sdsdot.f 💖

okay bestie, we're in the LAPACK BLAS section and this page is literally all about BLAS/SRC/sdsdot.f — one tiny file, one very cute function, and she's the main character of this whole doc. pull up a chair 🫶

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✨ SYNOPSIS ✨

Functions/Subroutines

real function sdsdot (n, sb, sx, incx, sy, incy)

• SDSDOT — that's her. that's the girl. 🎀

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📖 Function/Subroutine Documentation 📖

real function sdsdot

real function sdsdot (integer n, real sb, real, dimension(*) sx, integer
    incx, real, dimension(*) sy, integer incy)

SDSDOT 💅

🌸 Purpose 🌸

so what does she DO? she computes the inner product of two vectors with extended precision accumulation. like, she's doing the math in double precision and handing you back a single precision result. no cap, that's the whole vibe.

• Returns S.P. result with dot product accumulated in D.P.
• The formula, verbatim, because we do NOT paraphrase math:

SDSDOT = SB + sum for I = 0 to N-1 of SX(LX+I*INCX)*SY(LY+I*INCY)

where LX = 1 if INCX .GE. 0, else LX = 1+(1-N)*INCX, and LY is defined in a similar way using INCY.

so cute, so precise, so iconic ✨

🧚 Parameters 🧚

• N — N is INTEGER. it's the number of elements in the input vector(s). the headcount bestie 💜
• SB — SB is REAL. a single precision scalar that gets added to the inner product. she's the little bonus sprinkle on top 🍓
• SX — SX is REAL array, dimension ( 1 + ( N - 1 )*abs( INCX ) ). single precision vector with N elements. she's bringing the numbers ✨
• INCX — INCX is INTEGER. the storage spacing between elements of SX. think of it as how far apart the girls are standing in the array 💅
• SY — SY is REAL array, dimension ( 1 + ( N - 1 )*abs( INCX ) ). single precision vector with N elements. (yes, the dimension line says INCX right there, we are reading it exactly as it is, no editing on my watch 😭)
• INCY — INCY is INTEGER. the storage spacing between elements of SY. same energy as INCX, different letter 🦋

👑 Author 👑

• Lawson, C. L., (JPL), Hanson, R. J., (SNLA),
• Kincaid, D. R., (U. of Texas), Krogh, F. T., (JPL)
• Univ. of Tennessee
• Univ. of California Berkeley
• Univ. of Colorado Denver
• NAG Ltd.

the whole squad. legends only 🔥

📚 Further Details 📚

REFERENCES

C. L. Lawson, R. J. Hanson, D. R. Kincaid and F. T. Krogh, Basic linear algebra subprograms for Fortran usage, Algorithm No. 539, Transactions on Mathematical Software 5, 3 (September 1979), pp. 308-323.

REVISION HISTORY (YYMMDD)

okay this is the glow-up timeline and it is LONG. she's been evolving since 1979, we love a longevity queen 👑

• 791001 — DATE WRITTEN
• 890531 — Changed all specific intrinsics to generic. (WRB)
• 890831 — Modified array declarations. (WRB)
• 890831 — REVISION DATE from Version 3.2
• 891214 — Prologue converted to Version 4.0 format. (BAB)
• 920310 — Corrected definition of LX in DESCRIPTION. (WRB)
• 920501 — Reformatted the REFERENCES section. (WRB)
• 070118 — Reformat to LAPACK coding style

ngl the fact that there are TWO entries dated 890831? iconic. we do not question the archive, we simply respect it 🙈

📍 Definition at line 112 of file sdsdot.f. 📍

🖊️ Author 🖊️

Generated automatically by Doxygen for LAPACK from the source code. (yes the page has an Author section twice — once for the humans, once for the robot. balance 💀)

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and that's the whole page, bestie!! you made it to the very end, so here's the cute sign-off: this was Version 3.12.0, dated Tue Nov 28 2023 12:08:41, and it belongs to the BLAS/SRC/sdsdot.f(3) page of LAPACK. go forth and dot those products, you absolute genius 🌈💖✨