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AccuracyGoal

さまざまな数値演算の最終結果の有効桁数を指定するオプションである．

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AccuracyGoal

AccuracyGoal

さまざまな数値演算の最終結果の有効桁数を指定するオプションである．

詳細

例題

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例  (2)

最低でも8桁確度まで数値積分を近似する：

Wolfram Language code: NIntegrate[Sin[x], {x, 0, 2 π}, AccuracyGoal -> 8]

ODEを解く際に，精度（相対誤差）を誤差制御の基準に使う：

Wolfram Language code: s = NDSolve[{x'[t] == x[t], x[0] == 10 ^ -20}, x, {t, 0, 1}, AccuracyGoal -> ∞]

相対誤差は小さい：

Wolfram Language code: relerr[t_] = 1 - x[t] / (Exp[t] 10 ^ -20);
Wolfram Language code: relerr[1] /. s

AccuracyGoalを指定しないと相対誤差はずっと大きくなる：

Wolfram Language code: relerr[1] /. NDSolve[{x'[t] == x[t], x[0] == 10 ^ -20}, x, {t, 0, 1}]

スコープ  (2)

収束基準とを使って最小値を求める：

Wolfram Language code: f[x_] = Sin[x ^ 2];
Wolfram Language code: FindMinimum[f[x], {x, 2}, AccuracyGoal -> 10, PrecisionGoal -> 8]

収束基準とを使う：

Wolfram Language code: FindMinimum[f[x], {x, 2}, AccuracyGoal -> 10, PrecisionGoal -> ∞]

機械精度では不可能な収束基準とを使う：

Wolfram Language code: FindMinimum[f[x], {x, 2}, AccuracyGoal -> 20, PrecisionGoal -> ∞]

作業精度を上げて収束させる：

Wolfram Language code: FindMinimum[f[x], {x, 2}, AccuracyGoal -> 20, PrecisionGoal -> ∞, WorkingPrecision -> 40]

高精度演算で微分方程式を解く：

Wolfram Language code: s32 = NDSolve[{x''[t] + x'[t] ^ 2 + x[t] ^ 5 == 0, x[0] == 1, x'[0] == 0}, x, {t, 0, 5}, WorkingPrecision -> 32]
Wolfram Language code: Plot[x[t] /. s32, {t, 0, 5}]

AccuracyGoalとPrecisionGoalを32桁の作業精度の半分で使う：

Wolfram Language code: sag = NDSolve[{x''[t] + x'[t] ^ 2 + x[t] ^ 5 == 0, x[0] == 1, x'[0] == 0}, x, {t, 0, 5}, WorkingPrecision -> 32, AccuracyGoal -> 16, PrecisionGoal -> 16]

これは，NDSolveで使われる自動設定に相当する：

Wolfram Language code: s32 === sag
Wolfram Research (1988), AccuracyGoal, Wolfram言語関数， https://reference.wolfram.com/language/ref/AccuracyGoal.html （2003年に更新）.

テキスト

Wolfram Research (1988), AccuracyGoal, Wolfram言語関数， https://reference.wolfram.com/language/ref/AccuracyGoal.html （2003年に更新）.

CMS

Wolfram Language. 1988. "AccuracyGoal." Wolfram Language & System Documentation Center. Wolfram Research. Last Modified 2003. https://reference.wolfram.com/language/ref/AccuracyGoal.html.

APA

Wolfram Language. (1988). AccuracyGoal. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/AccuracyGoal.html

BibTeX

@misc{reference.wolfram_2026_accuracygoal, author="Wolfram Research", title="{AccuracyGoal}", year="2003", howpublished="\url{https://reference.wolfram.com/language/ref/AccuracyGoal.html}", note=[Accessed: 07-August-2026]}

BibLaTeX

@online{reference.wolfram_2026_accuracygoal, organization={Wolfram Research}, title={AccuracyGoal}, year={2003}, url={https://reference.wolfram.com/language/ref/AccuracyGoal.html}, note=[Accessed: 07-August-2026]}