{"id":160,"date":"2025-12-02T12:56:13","date_gmt":"2025-12-02T04:56:13","guid":{"rendered":"https:\/\/snakesleep.work\/?p=160"},"modified":"2025-12-02T12:59:35","modified_gmt":"2025-12-02T04:59:35","slug":"%e4%bc%98%e5%8c%96%e5%99%a8%ef%bc%88optimizer%ef%bc%89","status":"publish","type":"post","link":"https:\/\/snakesleep.work\/?p=160","title":{"rendered":"\u4f18\u5316\u5668\uff08optimizer\uff09"},"content":{"rendered":"\n<h1 class=\"wp-block-heading\">PyTorch torch.optim \u4f18\u5316\u5668\u6a21\u5757<\/h1>\n\n\n\n<p>\u4f18\u5316\u5668\u662f\u6df1\u5ea6\u5b66\u4e60\u4e2d\u7684\u6838\u5fc3\u7ec4\u4ef6\uff0c\u8d1f\u8d23\u6839\u636e\u635f\u5931\u51fd\u6570\u7684\u68af\u5ea6\u8c03\u6574\u6a21\u578b\u53c2\u6570\uff0c\u4f7f\u6a21\u578b\u80fd\u591f\u9010\u6b65\u903c\u8fd1\u6700\u4f18\u89e3\u3002\u5728PyTorch\u4e2d\uff0c<code>torch.optim<\/code>\u6a21\u5757\u63d0\u4f9b\u4e86\u591a\u79cd\u4f18\u5316\u7b97\u6cd5\u7684\u5b9e\u73b0\u3002<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">1. \u4e3a\u4ec0\u4e48\u9700\u8981\u4f18\u5316\u5668<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>\u81ea\u52a8\u5316\u53c2\u6570\u66f4\u65b0<\/strong>\uff1a\u624b\u52a8\u8ba1\u7b97\u548c\u66f4\u65b0\u6bcf\u4e2a\u53c2\u6570\u975e\u5e38\u7e41\u7410<\/li>\n\n\n\n<li><strong>\u52a0\u901f\u6536\u655b<\/strong>\uff1a\u4f7f\u7528\u4f18\u5316\u7b97\u6cd5\u6bd4\u666e\u901a\u68af\u5ea6\u4e0b\u964d\u66f4\u5feb\u627e\u5230\u6700\u4f18\u89e3<\/li>\n\n\n\n<li><strong>\u907f\u514d\u5c40\u90e8\u6700\u4f18<\/strong>\uff1a\u67d0\u4e9b\u4f18\u5316\u5668\u5177\u6709\u8df3\u51fa\u5c40\u90e8\u6700\u4f18\u7684\u80fd\u529b<\/li>\n<\/ul>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>\u4f18\u5316\u5668\u540d\u79f0<\/th><th>\u4e3b\u8981\u7279\u70b9<\/th><th>\u9002\u7528\u573a\u666f<\/th><\/tr><\/thead><tbody><tr><td>SGD<\/td><td>\u7b80\u5355\u57fa\u7840<\/td><td>\u57fa\u7840\u6559\u5b66\u3001\u7b80\u5355\u6a21\u578b<\/td><\/tr><tr><td>Adam<\/td><td>\u81ea\u9002\u5e94\u5b66\u4e60\u7387<\/td><td>\u5927\u591a\u6570\u6df1\u5ea6\u5b66\u4e60\u4efb\u52a1<\/td><\/tr><tr><td>RMSprop<\/td><td>\u9002\u5e94\u5b66\u4e60\u7387<\/td><td>RNN\u7f51\u7edc<\/td><\/tr><tr><td>Adagrad<\/td><td>\u53c2\u6570\u72ec\u7acb\u5b66\u4e60\u7387<\/td><td>\u7a00\u758f\u6570\u636e<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\">2. \u4f18\u5316\u5668\u6838\u5fc3API<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">2.1 \u57fa\u672c\u4f7f\u7528\u6d41\u7a0b<\/h3>\n\n\n\n<pre class=\"wp-block-code\"><code>import torch.optim as optim\n\n# 1. \u5b9a\u4e49\u6a21\u578b\nmodel = MyModel()\n\n# 2. \u521b\u5efa\u4f18\u5316\u5668\u5b9e\u4f8b\noptimizer = optim.Adam(model.parameters(), lr=0.001)\n\n# 3. \u8bad\u7ec3\u5faa\u73af\nfor epoch in range(epochs):\n    # \u524d\u5411\u4f20\u64ad\n    outputs = model(inputs)\n    loss = criterion(outputs, labels)\n    \n    # \u53cd\u5411\u4f20\u64ad\n    optimizer.zero_grad()  # \u6e05\u7a7a\u68af\u5ea6\n    loss.backward()        # \u8ba1\u7b97\u68af\u5ea6\n    \n    # \u53c2\u6570\u66f4\u65b0\n    optimizer.step()       # \u66f4\u65b0\u53c2\u6570<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\">2.2 \u5173\u952e\u65b9\u6cd5\u8bf4\u660e<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>zero_grad()<\/strong>\uff1a\u6e05\u7a7a\u53c2\u6570\u7684\u68af\u5ea6\u7f13\u5b58<\/li>\n\n\n\n<li><strong>step()<\/strong>\uff1a\u6267\u884c\u5355\u6b21\u53c2\u6570\u66f4\u65b0<\/li>\n\n\n\n<li><strong>state_dict()<\/strong>\uff1a\u83b7\u53d6\u4f18\u5316\u5668\u72b6\u6001\uff08\u53ef\u7528\u4e8e\u4fdd\u5b58\u548c\u52a0\u8f7d\uff09<\/li>\n\n\n\n<li><strong>load_state_dict()<\/strong>\uff1a\u52a0\u8f7d\u4f18\u5316\u5668\u72b6\u6001<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">3. \u5e38\u7528\u4f18\u5316\u5668\u8be6\u89e3<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">3.1 SGD (\u968f\u673a\u68af\u5ea6\u4e0b\u964d)<\/h3>\n\n\n\n<pre class=\"wp-block-code\"><code>optim.SGD(params, lr=0.01, momentum=0, dampening=0, \n          weight_decay=0, nesterov=False)<\/code><\/pre>\n\n\n\n<p><strong>\u6838\u5fc3\u53c2\u6570<\/strong>\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><code>lr<\/code>&nbsp;(float)\uff1a\u5b66\u4e60\u7387\uff08\u9ed8\u8ba40.01\uff09<\/li>\n\n\n\n<li><code>momentum<\/code>&nbsp;(float)\uff1a\u52a8\u91cf\u56e0\u5b50\uff08\u9ed8\u8ba40\uff09<\/li>\n\n\n\n<li><code>weight_decay<\/code>&nbsp;(float)\uff1aL2\u6b63\u5219\u5316\u7cfb\u6570\uff08\u9ed8\u8ba40\uff09<\/li>\n<\/ul>\n\n\n\n<p><strong>\u7279\u70b9<\/strong>\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u6700\u7b80\u5355\u7684\u4f18\u5316\u7b97\u6cd5<\/li>\n\n\n\n<li>\u53ef\u4ee5\u6dfb\u52a0\u52a8\u91cf\u9879\u52a0\u901f\u6536\u655b<\/li>\n\n\n\n<li>\u9002\u5408\u4f5c\u4e3a\u57fa\u51c6\u6bd4\u8f83<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">3.2 Adam (\u81ea\u9002\u5e94\u77e9\u4f30\u8ba1)<\/h3>\n\n\n\n<pre class=\"wp-block-code\"><code>optim.Adam(params, lr=0.001, betas=(0.9, 0.999), \n           eps=1e-08, weight_decay=0, amsgrad=False)<\/code><\/pre>\n\n\n\n<p><strong>\u6838\u5fc3\u53c2\u6570<\/strong>\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><code>betas<\/code>&nbsp;(Tuple[float, float])\uff1a\u7528\u4e8e\u8ba1\u7b97\u68af\u5ea6\u548c\u68af\u5ea6\u5e73\u65b9\u7684\u79fb\u52a8\u5e73\u5747\u7cfb\u6570<\/li>\n\n\n\n<li><code>eps<\/code>&nbsp;(float)\uff1a\u6570\u503c\u7a33\u5b9a\u9879\uff08\u9ed8\u8ba41e-8\uff09<\/li>\n\n\n\n<li><code>amsgrad<\/code>&nbsp;(bool)\uff1a\u662f\u5426\u4f7f\u7528AMSGrad\u53d8\u4f53\uff08\u9ed8\u8ba4False\uff09<\/li>\n<\/ul>\n\n\n\n<p><strong>\u7279\u70b9<\/strong>\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u81ea\u9002\u5e94\u5b66\u4e60\u7387<\/li>\n\n\n\n<li>\u7ed3\u5408\u4e86\u52a8\u91cf\u6982\u5ff5<\/li>\n\n\n\n<li>\u5927\u591a\u6570\u60c5\u51b5\u4e0b\u7684\u9ed8\u8ba4\u9009\u62e9<\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">4. \u4f18\u5316\u5668\u9ad8\u7ea7\u6280\u5de7<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">4.1 \u5b66\u4e60\u7387\u8c03\u5ea6<\/h3>\n\n\n\n<pre class=\"wp-block-code\"><code>from torch.optim.lr_scheduler import StepLR\n\noptimizer = optim.SGD(model.parameters(), lr=0.1)\nscheduler = StepLR(optimizer, step_size=30, gamma=0.1)\n\nfor epoch in range(100):\n    train(...)\n    validate(...)\n    scheduler.step()  # \u66f4\u65b0\u5b66\u4e60\u7387<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\">4.2 <strong>\u53c2\u6570\u5206\u7ec4\u4f18\u5316<\/strong>\uff1a<\/h3>\n\n\n\n<pre class=\"wp-block-code\"><code>optim.SGD(&#91;\n    {'params': model.base.parameters()},  # \u57fa\u7840\u5c42\n    {'params': model.classifier.parameters(), 'lr': 1e-3}  # \u5206\u7c7b\u5c42\n], lr=1e-2)\n<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>4.3 \u68af\u5ea6\u88c1\u526a<\/strong>\uff1a<\/h3>\n\n\n\n<pre class=\"wp-block-code\"><code>torch.nn.utils.clip_grad_norm_(model.parameters(), max_norm=1.0)<\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"<p>PyTorch torch.optim \u4f18\u5316\u5668\u6a21\u5757 \u4f18\u5316\u5668\u662f\u6df1\u5ea6\u5b66\u4e60\u4e2d\u7684\u6838\u5fc3\u7ec4\u4ef6\uff0c\u8d1f\u8d23\u6839\u636e\u635f\u5931\u51fd\u6570\u7684\u68af\u5ea6\u8c03\u6574\u6a21 [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[20],"tags":[21],"class_list":["post-160","post","type-post","status-publish","format-standard","hentry","category-20","tag-21"],"_links":{"self":[{"href":"https:\/\/snakesleep.work\/index.php?rest_route=\/wp\/v2\/posts\/160","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/snakesleep.work\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/snakesleep.work\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/snakesleep.work\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/snakesleep.work\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=160"}],"version-history":[{"count":4,"href":"https:\/\/snakesleep.work\/index.php?rest_route=\/wp\/v2\/posts\/160\/revisions"}],"predecessor-version":[{"id":165,"href":"https:\/\/snakesleep.work\/index.php?rest_route=\/wp\/v2\/posts\/160\/revisions\/165"}],"wp:attachment":[{"href":"https:\/\/snakesleep.work\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=160"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/snakesleep.work\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=160"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/snakesleep.work\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=160"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}